Bilingualism is defined as the ability to communicate or be fluent in two languages. Multilingualism (a related term) refers to the ability to communicate or be fluent in three or more languages. Early definitions dating back to the 1930s refer to bilingualism as having “native-like” control of two languages. Nevertheless, research in the fields of linguistics, psychology, sociology, education, neurology, and politics has expanded the concept of bilingualism far beyond the simplistic view of communicating in two languages. Current definitions are as complex as each of the languages a bilingual individual chooses to communicate in.

An important distinction necessary to begin to understand the concept of bilingualism is the difference between ability (or degree of bilingualism) and use (or function of bilingualism). To communicate proficiently in a given language, an individual must possess four basic skills: listening, speaking, reading, and writing. Some have argued for the inclusion of thinking as a fifth language ability. To use the abilities properly, a bilingual individual must exist in what is known as a language community, for these abilities do not develop in a vacuum. Moreover, contact between different language communities provides the bilingual individual with the context to know when to listen, speak, read, write, and think in which language.

Language Ability

Human beings are uniquely equipped for language production. The brain performs all the executive functions (such as information processing and controlling the physical aspects of speech). The diaphragm muscle, lungs, nose, mouth, lips, tongue, and vocal cords are all involved in speech production and regulation. The ear, ear bones, cochlea, brain stem, and auditory cortex are involved in hearing. Facial expressions and hand gestures also play a role in spoken language as well as sign language.

These actions of language performance represent the outward evidence that an individual has language competence. Language competence is the general term that lets us know an individual is proficient in a given language (e.g., that an individual has a mental system established for that particular language and can analyze and produce it). Language abilities are the more specific, direct, and quantifiable evidence that an individual can communicate in a given language.

Language abilities are multidimensional in nature. They include active skills (e.g., speaking and writing) and passive skills (e.g., listening and reading). A person may speak a language but not be able to read in that language or understand the spoken language. An individual may understand others who speak in a given language but not be able to speak it themselves. These abilities can be developed formally (e.g., school, continuing education classes), informally (e.g., contact with another language community such as friends or the media), or through a mixture of both formal and informal methods (e.g., language immersion programs, living abroad).

An individual who can only communicate in one language is referred to as a monolingual (or monoglot). An individual who has developed an approximately equal level of proficiency in her or his language abilities across a variety of situations in both languages is commonly referred to as a balanced bilingual. This is what most people typically think of when referring to bilingual individuals: a person who is equally fluent and has the same knowledge base in two languages. It is important to note that being monolingual may not necessarily be a good reference point to compare with or understand bilinguals.

Dominant bilingualism is another type of bilingual-ism used to describe a person who can communicate in two languages but is partial to one of them because she or he is more proficient in it. Although not always the case, this more proficient language is usually the one the person learned first (e.g., their first language, native language, or mother tongue). Another type of bilingual-ism is called semilingualism (or distractive bilingual-ism). This controversial term describes an individual who has some deficiencies in both languages when compared with monolinguals in each of those languages. These deficiencies typically include a smaller vocabulary, incorrect grammar, lack of creativity and spontaneity with both languages, and a difficulty with thinking and expressing emotions in either language. The term has been wrought with controversy because of its negative connotations and its emphasis on expectations of failure and underachievement.

Language Use

The experience of a bilingual individual is not independent of her or his context. Contact between different language communities helps languages grow, helps individuals learn their language(s) better, and helps communities relate better with each other. Studying functional bilingualism facilitates the understanding of a bilingual individual’s language use in the context of her or his language community.

Understanding language use in bilingualism entails exploring the following questions: (a) Who is the speaker? (b) Who is the listener(s)? (c) What is the situation or context? (d) What is the specific topic of conversation? and (e) What is the purpose of language use? For example, why does speaker A change from Spanish to English when talking to listener B at location C about topic D? How is it that speaker E can talk in English to speaker F when the topic is G but not when the topic is H? Understanding bilingual communication thus moves beyond the concept of language proficiency and language skills.

The term diglossia refers to the notion of a community having more than one language available for use. The situation typically involves a majority (or high language variety) and a minority (or low variety) language. Language communities often perceive a majority language as more prestigious and as the key to upward mobility. They thus tend to use it in formal or official contexts (e.g., school, business, correspondence with the government). Minority languages are more often used in informal or personal situations (e.g., home, family, correspondence with friends). For example, a television reporter in Hawai’i may talk about a football game during a broadcast in standard English but discuss it with her friends at home in pigeon English (a form of English that retains its basic grammatical rules while integrating those of other languages such as Hawaiian, Japanese, Chinese, and Portuguese).

This phenomenon of language shift is often visible in immigrant populations. First-generation immigrants maintain their own language while attempting to learn the host language. Second-generation immigrants intent on assimilating to the majority culture embrace the host language and begin using it in contexts once reserved for their native language. By the time third-generation immigrants choose a language in which to communicate, the majority language may be the only choice available to them.

Code-switching is a common phenomenon that occurs when a bilingual individual alternates between languages. It can happen in complete sentences, within one sentence, or at the single word level. “Voy a printear el homework” (I’m going to print the homework) is an example of code-switching. Code-switching is what some members of the Spanish-English bilingual community have termed spanglish.

Bilingualism Myths and Cognitive Advantages

The predominant belief during the “period of detrimental effects” (early 1800s to 1960s) was that bilingualism had a negative impact on individuals. It was thought that learning more than one language could confuse a child in the learning of their first language, could cause a decrease in intelligence (e.g., lower IQ), could decrease spiritual growth, and could cause cultural identity or split personality problems in children. Some also argued that two languages were learned independently of each other and that the knowledge of learning one did not transfer into the other. Others believed that as more was learned in one language, less could be learned in the other.

The “period of additive effects” (1960s-present) represented a shift in the understanding of bilingual-ism and its effects in cognitive development. Recent research has demonstrated that being mindful that there is more than one way to communicate enhances a number of cognitive skills. Flexibility, creativity, concept formation, memory, analogical reasoning, classification skills, divergent thinking, and inhibitory control are some of the advantages of bilingualism. Research has also shown that bilinguals develop increased metalinguistic skills (e.g., the ability to talk about language, analyze it, think about it, separate it from context, and judge it). This analysis of one’s own knowledge of language and control over this internal language process has been shown to facilitate earlier reading acquisition, which can lead to higher levels of academic achievement. Independent of academics, being able to communicate in two or more languages increases career opportunities and options for places to live, as well as a range of options for interpersonal interactions (which in turn enhances interpersonal skills). Finally, recent research has also shown that the increased cognitive activities inherent in bilingualism delay the onset of Alzheimer’s disease and other cognitive disorders.


  1. Baker, C. (2006). Foundations of bilingual education and bilingualism (4th ed.). Philadelphia: Multilingual Matters.
  2. Baker, C., & Jones, S. P. (1998). Encyclopedia of bilingualism and bilingual education. Clevedon, UK: Multilingual Matters.
  3. Bhatia, T. K., & Ritchie, W. C. (2004). The handbook of bilingualism. Oxford, UK: Blackwell.
  4. Bialystock, E. (2001). Bilingualism in development: Language, literacy, and cognition. Cambridge, MA: Cambridge University Press.
  5. Hakuta, K. (1990, Spring). Bilingualism and bilingual education: A research perspective. FOCUS: Occasional Papers in Bilingual Education (No. 1). Washington, DC: National Clearinghouse for Bilingual Education.
  6. Wei, L. (2000). The bilingualism reader. Oxford, UK: Routledge.

See also: